1. Field of the Invention
This invention relates generally to vehicle body panels, and more particularly, to movable body panels, such as doors, liftgates, hatches and the like.
2. Discussion of Related Art
Movable body panels for vehicles are typically made of sheet steel. Panels form closures for openings in the vehicle body. The sheets of the panel perform load bearing functions as well as ornamental functions. While steel sheets provide adequate strength in the panels, such panels are relatively heavy. In addition, corrosion caused by moisture, road salt and the like may deteriorate the integrity of the steel.
Relatively recently, body panels for vehicles have been made from thermoplastic materials. Such panels are typically lighter than steel panels. However, they do not always provide the desired rigidity and strength. In addition, such materials may be more costly than steel and may result in an inferior surface finish.
Examples of various constructions for body panels for vehicles are shown in U.S. Pat. Nos. 3,680,910; 4,799,730; 4,822,098; 4,880,267; and 5,102,186. U.S. Pat. No. 3,680,910 discloses a vehicle body closure panel formed from an inner panel and outer panel joined together by hem tanging the edge portions thereof. U.S. Pat. No. 4,799,730 discloses a movable tailgate for a vehicle having taillights mounted thereon. U.S. Pat. No. 4,822,098 discloses a double-walled plastic structural body panel for a vehicle. U.S. Pat. No. 4,880,267 discloses a back door for a motor vehicle that is hingedly mounted on the vehicle roof. U.S. Pat. No. 5,102,186 discloses a rear deck structure for a car for partly supporting a rear window glass elements and connecting opposite side walls of the car.
There remains a need for a movable vehicle body panel which is lightweight, has the desired degree of structural strength and rigidity, and which is an economical. replacement for steel and/or thermoplastic body panels.